racist dogs

My brother and his girlfriend adopted a dog, but their attempt was ill-fated. He writes:

So we are definitely "voting the dog out of the apartment" this week. While he is fun when he wants to be, he is also a freakin jerk a good portion of the time. He doesn't listen almost at all. He steals. He barks to ridiculous extents. He whines like a bitch. He tries to bite us sometimes (not hard but it still sucks). And he also tries to attack people of... how should I put this... colorful ethnic backgrounds. So yeah, Joey the dog turned out to be a big fat racist pain in the ass. It's really upsetting too. I had high hopes for this dog. He's such a smart dog. Unfortunately, he chooses to use his intelligence not for good, but instead for evil. Stupid dog.

I inquired about the dog's racism: does he discriminate based on skin tone alone -- barking louder in proportion to the darkness of the skin tone? Or is racist against one variety of non-white people exclusively? "How about tiny Japanese women?" I asked.  "Could you trick him with a tanned Caucasian, or an albino African-American?"

He replies: "Well so far we have found aversions to Mexican painters, a small black girl, and a very non-threatening Indian man. We do have a good sampling here in the DC area. He has yet to bump into any Asians though. I'm sure it is only a matter of time."

That dog's gotta go. I mean, I figured that if it were just one demographic -- for instance, tiny Japanese women-- then perhaps the dog was once beaten by a tiny Japanese woman and is thus reacting in a rationally protective manner. But I doubt this dog has experienced abuse at the hands of Mexican painters, a small black girl, and a very non-threatening Indian man.

How does a dog go so wrong?

Not that racist dogs weren't said to have been trained by police during the '60s. In lighter New Zealand faux-news, racist dog spoils dinner party.

I'm curious -- do dogs pick up racism from their (in this case, previous) owners, or might some dogs have a natural predilection to attack anyone who is ethnically dissimilar to their owners in an attempt to "protect" them? If the latter case, would Joey the Dog, if then adopted by a non-white person, begin to attack white people in an attempt to protect the new owner? Is this an entrenched racism, like that of humans, or might is be a malleable sort of xenophobia?